As good as a shopping mall to that extent sounds (and with good transport links, if trains stopped half hourly - and im sure a bus would work too!), I think businesses may be reluctant to investing in such an area, with it being close to Teesside Park, Darlington & Middlesbrough - all of which have a large presence of the Big Brand names.
In all honesty though, it could be a good shout; what with Peel's previous history of shopping centre management.
But, only time will tell, I suppose.